Show that the tangent of an angle between the lines `x/a+y/b=1` and `x/b-y/b=1\ i s(2a b)/(a^2-b^2)`

Explanation

Given `x/a + y/b = 1 …(i)`


Slope, `m1 = -b/a`


`x/a – y/b = 1 …(ii)`


Slope, `m2 = b/a`


...